Integrated circuits (ICs) are widely used in many electronic devices. A typical IC includes a silicon die in which are formed a number of active semiconductor devices, such as transistors, and passive devices, such as resistors. The integrated circuit die must typically be connected to other circuit components. Accordingly, the IC is typically protected by a surrounding package, such as formed of molded plastic, and a plurality of leads extend outwardly from the package for electrical connection to associated components. In addition, ICs are becoming more complex while remaining the same size or also becoming smaller. Accordingly, more connections to external circuits may be desirable.
One advantageous method of protecting the IC with a package is the so-called direct chip attachment (DCA) method. According to DCA, the IC is attached face down directly to the printed circuit board or carrier. Electrical connections may be made by solder bumps which are reflowed between pads on the chip and corresponding pads on the printed circuit board, for example.
Alternately, as disclosed, for example, in U.S. Pat. No. 5,543,585 to Booth et al., an adhesive may be applied between the IC and substrate for mechanical and electrical connection. The patent also discloses an embodiment wherein conductive pegs are positioned on the pads, then a prepunched insulative adhesive film is fitted over the pads and applied to the substrate surface.
Unfortunately, complex and highly specialized equipment is needed to precisely align and connect the chip to the printed circuit board. Accordingly, conventional DCA is relatively expensive, in part, because the specialized equipment is suitable only for DCA and is not usable for other routine assembly procedures.